The availability of the Internet enables new methods of directly distributing multimedia files and realtime media transmission to end-users in an electronic format. The advantages associated with electronic distribution are pushing providers of media content to establish global distribution systems for digital content.
The availability of new compression algorithms for multimedia data has dramatically reduced the bandwidth and storage space required for the electronic distribution of these data. It enables a more efficient distribution of the data, and at a higher definition. In the coming years, the availability of broadband will encourage a significant part of the media industry to adopt the Internet as a distribution channel in direct competition with established channels such as cable or satellite TV.
Prior art systems provide various ways for transmitting multimedia such as voice and video over the Internet. Real-time streaming systems over the Internet, such as Microsoft, Real-Networks, SeaChange, and Broadbus deliver systems for real-time streaming content over the Internet. However, all of these systems operate in a ‘centralistic’ mode in which a server located in one point delivers the media (realtime or to be downloaded first and watched later) to the content consumers. One drawback associated with such prior art systems is the need to allocate bandwidth in the center to satisfy the needs of the consumers.
Distributed networks enable the media to be transmitted from one consumer to another without the need for centralistic streaming servers. As an example, peer-to-peer file sharing systems for PCs are well known in the industry and are a very efficient technology that can be used to deliver media content in a legitimate manner (such as AOL HI-Q, BBC) to complement or replace traditional client-server download or streaming. Examples for such peer-to-peer systems are Bittorrent and Gnutella. All of the above systems do not distribute the files (media or software) in realtime. User can download the files and consume them afterwards, but, generally speaking, they cannot consume the media while downloading it.
Realtime streaming over a peer-to-peer network is a new phenomenon and examples of such systems are Coolstream (proposed in 2004 by Xinyan Zhang et. “Coolstream: A Data Driver Overlay Network for Efficient Live Media Streaming), and CollectCast: (proposed in 2003 by Hefeeda et all “PROMISE: peer-to-peer media streaming using CollectCast” in Proc. Of ACM Multimedia 2003 pages 45-54). However, these systems do not take into consideration the asymmetric nature of the real-world network, thus the fact that common values of upload bandwidth from nodes in the real-world network versus the download limits of the nodes. As an example, in ADSL network, as well as in Cable networks, the download bandwidth supplied to the users is lower than their available upload bandwidth.
There is, thus, a need in the art, to introduce the concept of nodes that act in the role of Amplifiers and upload more bandwidth to the network than the one they download.